1. Field of the Invention
This invention relates to the heat stabilization of carotenoid-colored edible oils.
2. Description of the Prior Art
Borenstein in U.S. Pat. No. 3,039,877 discloses stabilized carotenoid compositions wherein the carotene stabilizer is selected from the group consisting of at least one of butylated hydroxyanisole, alpha-propyl gallate, nordihydroguaiaretic acid and butylated hydroxytoluene. In column 2 thereof, Borenstein teach away from the use of lauryl thiodipropinate as a stabilizer for carotene at elevated temperatures of 325.degree. F. or above.
In U.S. Pat. No. 3,585,223, Hitoshi et al teach the use of cystine to stabilize animal or vegetable origin fats against oxidation. Fat-soluble vitamins, such as beta-carotene, vitamin A and vitamin E are included within the fats with which cystine acts as a stabilizer against oxidation.
In U.S. Pat. No. 4,169,901 to Kravis, deep-fat frying compositions are disclosed containing antioxidants such as butylated hydroxytoluene, butylated hydroxyanisole and citric acid.
Carotenoid, particularly carotene, compositions are useful as food coloring additives, particularly when the compositions are not subjected to high temperatures. In high temperature applications, appreciable decomposition of the carotenoid is found to occur starting at temperatures of from about 250.degree. F. to about 375.degree. F. The oxidation stabilizers that have been used in the past in cartenoid-containing compositions have not been entirely satisfactory in preventing severe bleaching of the color imparted by the carotenoid as a result of oxidation.